[llvm] [TailDuplicator] Add a limit on the size of predecessors (PR #78582)

[Nikita Popov via llvm-commits]

nikic wrote:

We should not implement profile-guided optimizations based on hypotheticals. Did you *actually* run benchmarks with this patch and saw regressions? (How large?) If not, we should do the straightforward thing until there is evidence that something more complex is justified.

https://github.com/llvm/llvm-project/pull/78582